(Determinating of the surface reactivity of coal powders). Final report. [4t-butylpyridine; 2,6-di-t-butylpyridine; 3,5-di-t-butylphenol; 2,6-di-t-butylphenol]

Technical Report · Fri Dec 13 00:00:00 EST 1985

OSTI ID:6024514

Fowkes, F M

Techniques have been developed for study of the chemistry of the surface sites of coal powders. Conclusions of this study are as follows: (1) The surface of coal powders is heavily populated with acidic and basic sites with acid strengths on the order of phenol and with basic sites on the order of pyridine. (2) The surface population of acidic and basic sites is measurable by adsorption of t-butyl substituted organic acids and bases from solvents such as iso-octane, for the t-butyl group blocks penetration into the coal. (3) Flow calorimetric studies of the adsorption of t-butylated acid-base probes onto powdered coal allow accurate determination of the heats of adsorption and desorption. (4) Acid-base probes without the t-butyl group penetrate so deeply into coal powder particles that their desorption is quite incomplete. (5) Vacuum-oven drying of powdered coal reduces several-fold the amount of surface available for adsorption of acid-base probes. (6) The outer surface area of coal powders can be determined quantitatively by adsorption of t-butylated acid-base probes. The surface areas agree with those determined by gas adsorption with gases which do not hydrogen bond. (7) The adsorption of carbon dioxide into coal or any other polymer capable of acid-base interactions is shown to be a swelling phenomenon, unrelated to porosity. (8) Electrophoresis of coal powders in organic acids or bases is found to be a quick and easy way to determine if the surface has acidic or basic sites. (9) Electrophoresis of coal powders in acetonitrile provides a method of determining whether the surface of coal is predominantly acidic or basic; acidic coals are charged negatively and basic coals are charged positively. 11 refs., 5 figs., 12 tabs.

• Research Organization: Lehigh Univ., Bethlehem, PA (USA). Dept. of Chemistry
• DOE Contract Number: FG22-82PC50809
• OSTI ID: 6024514
• Report Number(s): DOE/PC/50809-T11; ON: DE86006821
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ANTHRACITE
SURFACE AREA
SURFACE PROPERTIES
BITUMINOUS COAL
CARBON DIOXIDE
ADSORPTION
DESORPTION
PHENOLS
ADSORPTION HEAT
PYRIDINES
CALORIMETRY
ELECTROPHORESIS
EXPERIMENTAL DATA
FOURIER TRANSFORMATION
GRINDING
INFRARED SPECTRA
NITROGEN
PH VALUE
POWDERS
PROBES
RESEARCH PROGRAMS
AROMATICS
AZINES
BLACK COAL
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
COAL
COMMINUTION
DATA
ELEMENTS
ENERGY SOURCES
ENTHALPY
FOSSIL FUELS
FUELS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
INTEGRAL TRANSFORMATIONS
MACHINING
MATERIALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SORPTION
SPECTRA
THERMODYNAMIC PROPERTIES
TRANSFORMATIONS
010600* - Coal
Lignite
& Peat- Properties & Composition